ZOOM OPTICAL SYSTEM, EXPOSURE DEVICE EQUIPPED WITH ZOOM OPTICAL SYSTEM AND EXPOSING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a zoom optical system capable of securing a required magnification ratio without substantially changing the positions of an object surface and an image surface and the positions of an entrance pupil and an exit pupil in the case of changing a focal distance. SOLUTION: In the case of changing the focal distance between a maximum focal distance state (a) and a minimum focal distance state (d), at least two lens groups are moved along a specified orbit. The specified orbit is set so as not to substantially change the positions of the object surface and the image surface and the positions of the entrance pupil and the exit pupil. In the case of changing the focal distance to the minimum focal distance state, the lens group (G2) having negative refractive power is moved to an object side, and in the case of changing the focal distance to the maximum focal distance state, the lens group (G2) having the negative refractive power is moved to an image side.